This research studies single motherhood by focusing on the dynamic nature of family experience and, in particular, the complex ways in which family change during childhood and adolescence affects transitions into sexual activity, fertility, and family formation. We examine change by: (a) directly adjudicating between alternative hypotheses about the effect of past and current family situation on the risk of single motherhood; (b) testing assumptions about persistence versus transience using models that let family situation have constant, declining, increasing, or nonmonotonic effects with age or duration; (c) employing dynamic models to clarify the behavioral mechanisms underlying selection into, and exit out of, joint fertility and marital statuses; and (d) modeling the intergenerational-transmission of disadvantage using mother/adolescent data. We have four specific aims. First, we use data from the National Longitudinal Surveys of Youth (NLSY) and National Survey of Families and Households (NSFH) to adjudicate directly between several hypotheses implicated by previous research as critical antecedents of single motherhood. Second, we test hypotheses on continuity and discontinuity in the life course, including direct assessments of: (a) persistent effects of growing up in a nonintact family during early childhood; (b) transient effects experienced by children during the period following a parental divorce, separation, or death; (c) long-term effects, including gender-specific effects, of parental divorce, separation, or death; and (d) factors influencing the degree of persistence or speed with which a transient effect declines in magnitude. Third, we study possible selection mechanisms governing a woman's age-graded risk of entry into, and exit out of, joint parity and marital states. Fourth, we examine the intergenerational consequences of single motherhood using NSFH data on mothers and adolescents to study: (a) parent/child interactions, in particular, the link between the childhood and adolescent family experiences of NSFH respondents and their ability as parents to constrain, influence, and monitor the sexual and dating behaviors of their adolescent children; and (b) selection mechanisms across generations using models of mother/child similarity in the early adult transitions of parents and their adolescent children.